The present invention relates to a thermal film structure containing at least two imaging layers with different processing characteristics. More specifically the present invention relates to a thermal film structure having a high temperature imaging layer and a low temperature imaging layer, as well as a method for forming such a film.
In the conventional practice of color photography, silver halide film is developed by a chemical technique requiring several steps which include latent image developing, bleaching and fixing. While this technique has been developed over many years and results in exceptional images, the technique requires several chemicals and precise control of times and temperatures of development. Further, the conventional silver halide chemical development technique is not particularly suitable for utilization with compact developing apparatuses. The chemical technique which is a wet processing technique is also not easily performed in the home or small office.
Imaging systems that do not rely on conventional wet processing have received increased attention in recent years. Photothermographic imaging systems have been employed for producing silver images. Typically, these imaging systems have exhibited very low levels of radiation-sensitivity and have been utilized primarily where only low imaging speeds are required. A method and apparatus for developing a heat developing film is disclosed in U.S. Pat. No. 5,537,767. Summaries of photothermographic imaging systems are published Research Disclosure, Volume 170, June 1978, Item 17029, and Volume 299, March 1989, Item 29963. Heat development color photographic materials have been disclosed, for example, in U.S. Pat. No. 4,021,240 and U.S. Pat. No. 5,698,365.
U.S. Pat. No. 6,048,110 discloses an apparatus for thermal development which comprises the use of a thrust cartridge. Also, commercial products such as Color Dry Silver supplied from Minnesota Mining and Manufacturing Company and Pictography(trademark) and Pictrostat(trademark) supplied by Fuji Film Co., Ltd. have been on the market.
It is well known that photothermographic imaging layers can be constructed to process at a wide range of temperatures. For example, current thermal processes which process film in a high temperature range (hereinafter referred to as a HT Process), process films near 150 C for 20 sec, while some commercially available low speed black and white photothermographic films which process film in a low temperature range process the film at 120 C for 5 sec, (hereinafter referred to as a LT Process). The LT Process on a film intended for the HT Process would have no effect. However, the HT Process on a film intended for the LT Process would have the effect of developing the system to a uniform maximum density which would destroy images on the film unless they were somehow stabilized.
The present invention provides for a thermal film structure having at least two imaging layers with different processing characteristics. The thermal film structure of the present invention would permit the addition of metadata on one layer to enable the reading of such metadata while not effecting images on the other layer.
The present invention therefore provides for a thermal film structure which comprises a film support layer; a first imaging layer provided on one side of the film support layer which can be processed within a first temperature range; and a second imaging layer provided on a second side of the film support layer which can be processed within a second temperature range which is higher than the first temperature range.
The present invention also relates to a thermal film structure which comprises a film support layer; a first imaging layer provided on one side of the film support layer which can be processed within a first temperature range; and a second imaging layer provided on the one side of the film support layer which can be processed within a second temperature range that is higher than the first temperature range.
The present invention also relates to a method of forming a thermal film structure which comprises the steps of: providing a first imaging layer on one side of a film support layer, wherein the first imaging layer is adapted to be processed within a first temperature range; and providing a second imaging layer on a second side of the film support layer, wherein the second imaging layer is adapted to be processed within a second temperature range which is higher than the first temperature range.
The present invention further relates to a method of forming a thermal film structure which comprises the steps of: providing a first imaging layer on one side of a film support layer, wherein the first imaging layer is adapted to be processed within a first temperature range; and providing a second imaging layer on the one side of the film support layer, wherein the second imaging layer is adapted to be processed within a second temperature range which is higher than the first temperature range.
The present invention also relates to a thermal film structure which comprises a film support layer; a first imaging layer provided on one side of the film support layer, with the first imaging layer having first processing characteristics; and a second imaging layer provided on a second side of the film support layer, with the second imaging layer having second processing characteristics which are different from the first processing characteristics.
The present invention also relates to a thermal film structure which comprises a film support layer; a first imaging layer provided on one side of the film support layer, with the first imaging layer having first processing characteristics; and a second imaging layer provided on the one side of the film support layer, with the second imaging layer having second processing characteristics which are different from the first processing characteristics.
The present invention further relates to a method of processing a thermal film which comprises the steps of: providing a film containing a first imaging layer which is processable at a first temperature and a second imaging layer which is processable at a second temperature to a processor; processing the film a first time at the first temperature to develop the first imaging layer while not developing the second imaging layer; scanning the film after the first processing for obtaining information on said first imaging layer; and processing the film a second time at the second temperature to develop images on the second imaging layer while providing a uniform density to the first imaging layer, such that the first imaging layer does not affect a subsequent scanning of the film.